des,

I like a vortex on my bigger koi pond because they create so much mess, and
the less that goes to the filter, the better. I have about 20 fish in my
larger pond and some of them are over 10 pounds each. What they don't tear
up, they s*** on. Do you need one? Not necessarily. If you are using a
bead filter, I would recommend it. If you are using a veggie filter, it
could make a big difference in how often you have to clean the filter. If
you are using filter matting, it will significantly reduce maintenance. If
you have a small fish load, it can wait and be installed in two or three
years. I did mine as a retrofit.
--
RichToyBox
http://www.geocities.com/richtoybox/pondintro.html


"des" wrote in message
...
do i need a voertex for a5000 gal koi pond


des